Metric/ US conversion question

[SludgeMunkey]

Okay, so I am actually pretty proficient using the metric system (for being a lazy hillbilly American)
but I am a bit confused about standard conversational units. Back when I learned metric from my Canadian and Japanese counterparts in the defense industry, I was led to believe the centimeter is the standard unit used in technical conversations about dimensions, like the inch is used in the U.S.. I see that in fact it appears that I am wrong and the millimeter is better to use when discussing dimensions.

So is it more proper to say 30.4cm or 304mm?
(or should I keep up the stereotype and just say 12 inches?)

 

[blueberlin]

304 mm is best.

-Eva

 

[Jennewt]

I tend to use cm, but I'm another lazy hillbilly American. Also, I would just round it to 30 cm, unless there is a need for precision.

 

[blueberlin]

I agree with Jen - except that I am lousy at conversions and have this site bookmarked for easy reference. For general purposes it's enough to round off - for precision, it's down to milimeters, although I'd guess that that is only up to a meter as I have never seen anything referred to as eg 1111 mm.

-Eva

 

[oceanblue]

Standard SI (Système International d'Unités) units use mm and Metres. The preferred units are spaced a thousand apart, so you use mg gram Kilogram. Millimeter, Meter, Kilometer are the preferred units but there is nothing wrong with using the centimeter.

The centimeter was central in the metric system used prior to 1954, called the CGS system after Centimeter Gram Second, the SI units are Meter Kilogram Second or MKS.

0.3M, 300mm, 304mm if measured with great care are all correct. If you are going Imperial why not say about a foot instead of 12 inches!

 

[SludgeMunkey]

Ah, that clarifies it even more for me. The folks I worked with were older, so they probably learned in the 1954 standard.

Millimeters for me, it is then.

Thanks for the information folks!

 

[Azhael]

Like everything else, it´s relative. Depending on what kind of dimensions you are talking about you´ll use centimetres, metres, milimetres or whatever.
I personally only use milimetres when it´s actually needed.
For caudate sizes i would use centimetres...
In scientific articles there´s no consensus, centimetres or milimetres are used as the basic messure indistinctly...so it´s pretty much up to the individual....